Joshua Marsh wrote:


On 11/17/05, *William Yu* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:

     > No argument there.  But it's pointless if you are IO bound.

    Why would you just accept "we're IO bound, nothing we can do"? I'd do
    everything in my power to make my app go from IO bound to CPU bound --
    whether by optimizing my code or buying more hardware. I can tell you if
    our OLTP servers were IO bound, it would run like crap. Instead of < 1
    sec, we'd be looking at 5-10 seconds per "user transaction" and our
    users would be screaming bloody murder.

    In theory, you can always convert your IO bound DB to CPU bound by
    stuffing more and more RAM into your server. (Or partitioning the DB
    across multiple servers.) Whether it's cost effective depends on the DB
    and how much your users are paying you -- and that's a case-by-case
    analysis. Not a global statement of "IO-bound, pointless".


We all want our systems to be CPU bound, but it's not always possible. Remember, he is managing a 5 TB Databse. That's quite a bit different than a 100 GB or even 500 GB database.

I did say "in theory". :) I'm pretty sure google is more CPU bound than IO bound -- they just spread their DB over 50K servers or whatever. Not everybody is willing to pay for that but it's always in the realm of plausibility.

Plus we have to go back to the statement I was replying to which was "I have yet to come across a DB system that wasn't IO bound".


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